Industrial locking switches are commonly used in a variety of safety applications to prevent unauthorized or unintended access into a hazardous area. Switching devices, for example, are used for controlling devices in technical installations in a manner to prevent human access to machines, such as presses and so forth. Typically, such switching devices are configured to facilitate partial or complete shutdown of electrically driven machines/devices of the technical installation to avoid or reduce the opportunities of access to equipment when operational.
In another example, a safety interlock sensor is used to detect that a machinery guard door is closed before the machine operates. Industrial locking switches can be mounted on the hazard or non-hazard side of the door. The hazard side being the side of the guard door within which a person may be injured by operating machinery and the non-hazard side being on the outside of the guard door where no threat of injury exists.
When a locking switch detects that the actuator is present, a command signal can be sent to extend a locking plunger from the switch into an orifice in the actuator, thereby mechanically coupling the two parts and locking the guard door. Any attempt to bypass the lock by removing the actuator will cause the equipment on the hazard side to automatically shut down.
The guard door prevents partial or full-body access into the hazard side. In this scenario, the switch is assembled to a mounting bracket on the hazard side of the guard door and the complementary actuator is likewise assembled to the hazard side of the guard door. In this application, mounting the switch and actuator on the hazard side of the guard door prevents a person from tampering or attempting to bypass the locking switch because the person has no direct access to the switch and actuator.
However, if a person were to get trapped on the hazard side, for example, he/she may have to exit the area quickly to avoid the hazard. Therefore, it would be beneficial if an integral emergency escape release were provided or if provisions were made to allow a person to manually push down the locking plunger with a finger.